Wireless File Sharing: Win XP SP2 to Mac OSX 5.8

[tallbarb]

I recently switched to Comcast (a cable company) from DSL so have a
new cable modem and a new router that needed to set up for my wireless
network. I accepted all the defaults (it's an SMC Barricade). Now, I
can no longer see my Mac and my Mac no longer sees my PC. I had no
problem at all when I was with the other service (Qwest in Oregon).
They both connect to the wireless network just fine - internet access
is fine. I would assume the mapping for the shared drives/folders on
the Mac would be exactly the same as they were prior to the new
hardware - well, nothing works. I try to browse for a shared network
folder and the Mac isn't even listed, even though its set up for
Windows sharing. I have wasted at least 8 hours today trying to
figure out what is wrong - taking steps outlined in many different
posts on the subject - nothing has worked. Is there something I'm
missing? Maybe someone in this group can help - surely this isn't a
unique configuration? Any assistance would be very much appreciated!!!